Justin Trudeau and Andrew Scheer evoked the populism-fuelled political turmoil in the United States and Britain and the SNC-Lavalin scandal to vilify each other Thursday on the campaign trail.

The Liberal leader drew a link between his Conservative opponent and the instability caused by the impeachment drama unfolding in the U.S. and the Brexit agony that has racked the U.K. Trudeau revived his accusation that Scheer is relying on the “politics of fear” to scare voters.

Scheer returned to the SNC-Lavalin affair that has dogged Trudeau in recent months by promising a new law to investigate “sleazy” politicians.

Trudeau fired the first shot on Thursday, saying the uncertainty in the U.S. and U.K. serves as a warning to Canadians to resist the pull of divisive populism that he accuses his Conservative opponents of fostering.

While he did not mention President Donald Trump or Prime Minister Boris Johnson by name, Trudeau continued to link Scheer to other conservative politicians, such as Ontario Premier Doug Ford and former prime minister Stephen Harper.

Trudeau said Scheer is running on the same failed Harper policies as the Tories did in the 2015 campaign that brought the Liberals to power.

“Some of the consequences of the populist tendencies that we’ve seen over the past few years in places like the U.K. and the United States are clearly on display for Canadians right now,” Trudeau said in Sudbury, Ont., after announcing a series of new conservation measures.

It was the latest in a series of environment-related announcements this week, including a pledge to protect a quarter of Canada’s lands and oceans by 2025 and measures to help low-income families go camping in national and provincial parks.

Scheer responded with a scathing attack on Trudeau in his own backyard — the Montreal riding of Papineau — where he promised a Conservative government would launch a judicial inquiry into the SNC-Lavalin affair.

“It’s a cover-up on an historic scale,” said Scheer.

Scheer said he would introduce legislation that would allow the RCMP to ask the Supreme Court of Canada for access to information covered by cabinet confidence, saying it would prevent politicians from hiding behind the current system that’s meant to permit frank and open discussions among ministers.

NDP Leader Jagmeet Singh said Thursday he supports an inquiry and has been calling for one since the scandal erupted.

But he criticized Scheer for not saying whether he approves of deferred prosecution agreements in principle. Singh has said the NDP would do away with them.

“The root cause of this was a deferred prosecution agreement and he (Scheer) hasn’t talked about that,” Singh said in Campbell River, B.C., where he announced an NDP government would offer an annual rent subsidy of up to $5,000 to help families struggling to afford housing.

Singh was spending his third consecutive day in B.C. trying to protect some of his party’s ridings from a surging Green Party. Vancouver Island is where the Greens see their best chances of picking up seats, after a byelection win over the New Democrats in Nanaimo-Ladysmith in May.

Green Leader Elizabeth May was focused on breaking new ground in Quebec. She was in Montreal on Thursday, alongside several Quebec candidates, before her own participation in the Friday climate march.

“The province of Quebec has been playing a leadership role for a long time. We have in this country everything we need to make a change that ensures our children have a livable world,” she said.

“Regardless of where you’re from, or what party you used to vote for, if you’re listening to our children what you’re hearing is, ‘All hands on deck right now.’ “